Temporal pulse shaping for laser shock peening

ABSTRACT

Methods, systems, and apparatuses are disclosed for temporal pulse shaping of laser pulses used in laser shock peening applications. In one embodiment, a system for temporal pulse shaping of a laser beam used for laser shock peening comprises a laser; a modulator; a high voltage driver, a waveform generator, a polarizer, and an optical amplifier.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication No. 62/002,176, filed on May 22, 2014, which is incorporatedby reference herein in its entirety.

BACKGROUND

The laser shock peening (“LSP”) process, a substitute process fortraditional shot peening, is a cold working process used to produce acompressive residual stress layer and modify mechanical properties ofmaterials by impacting the material with enough force to create plasticdeformation. The residual stresses created by the LSP process increase amaterial's resistance to fatigue and stress, and the LSP process can beused to strengthen and harden materials. LSP uses high energy laserpulses to lase both transparent and opaque overlays on a surface of aworkpiece to generate a plasma plume and cause a rapid rise of pressureon the surface of a workpiece. This pressure creates and sustains ashockwave, which propagates through a workpiece material. The shockwavegenerated by LSP induces cold work into the microstructure of theworkpiece material and contributes to the increased performance of theworkpiece material. As the shockwave travels into the workpiece, some ofthe energy of the wave is absorbed during the plastic deformation of theworkpiece material. This is also known as cold working. The shockwavepermanently stretches the internal structure of the workpiece material.This plastic deformation generates compressive residual stresses in theworkpiece material, and increases the strength of the workpiecematerial. LSP uses a laser pulse width of about 5 nanoseconds (ns) toabout 40 ns and a typical spot diameter for a laser beam in LSP is about1.0 to about 6.0 mm. Fluence is the measure of energy delivered per unitarea, and in LSP applications, fluence is typically over 100 J/cm².

The present application appreciates that customizing a laser pulse forLSP applications may be a challenging endeavor.

SUMMARY

Systems and methods are provided for temporal pulse shaping of a pulsedlaser beam used in LSP applications.

In one embodiment, a system for temporal pulse shaping of a laser beamused for laser shock peening is provided, the system comprising: alaser; a modulator; a high voltage driver; a waveform generator; apolarizer; and an amplifier.

In another embodiment, a system for temporal pulse shaping of a pulsedlaser output used for laser shock peening is provided, the systemcomprising: a laser operable to produce a pulsed laser beam, wherein thelaser is at least one of: a diode pumped continuous wave laser, a diodepumped fiber laser, and a long pulse laser oscillator; a modulatoroperable to modulate the pulsed laser beam, wherein the modulator is atleast one of: an electro-optic modulator, an acousto-optic modulator,and an electro-optic Pockels cell; a high voltage driver operable tooutput a high voltage signal in response to an input waveform, the highvoltage driver operatively connected to the modulator and a waveformgenerator; the waveform generator, wherein the waveform generator isoperable to generate at least one waveform in response to a triggersignal from a processor, wherein the at least one waveform is input intothe high voltage driver to generate the high voltage signal; apolarizer, comprising a first polarization direction; and an amplifier,the amplifier operable to amplify the modulated pulsed laser beam tooutput an amplified, modulated, pulsed laser beam.

In another embodiment, a method for temporal pulse shaping of a laserbeam used in laser shock peening of a workpiece is provided, the methodcomprising the acts of: (1) determining at least one of: a desiredmagnitude of residual stress, and a desired depth of residual stress, atone or more locations on the workpiece and selecting a pulse width and atemporal profile of the laser beam corresponding to the at least one of:the desired magnitude of residual stress, and the desired depth ofresidual stress; (2) generating the laser beam with a laser andinputting the laser beam into a modulator; (3) generating a waveformfrom a waveform generator, wherein the waveform is based on the selectedpulse width and the selected temporal profile; (4) inputting thegenerated waveform into a high voltage driver to output a high voltagesignal; (5) inputting the high voltage signal into the modulator tomodulate and shape a temporal profile of the laser beam based on theselected pulse width and the selected temporal profile; (6) amplifyingthe modulated and shaped laser beam with an optical amplifier; (7)delivering the amplified, modulated, and shaped laser beam to the one ormore locations on the workpiece; and (8) repeating steps 1-7 for eachsubsequent location on the workpiece.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, which are incorporated in and constitute apart of the specification, illustrate various example systems, methods,and results, and are used merely to illustrate various exampleembodiments.

FIG. 1 illustrates a schematic view of an example system for temporalpulse shaping of a laser beam pulse.

FIG. 2 illustrates an example modification to a temporal profile of apulsed laser beam.

FIG. 3 illustrates an example embodiment of temporal pulse shaping for apulsed laser beam.

FIG. 4 is a flow chart illustrating an example method for temporal pulseshaping of a laser beam pulse.

DETAILED DESCRIPTION

Embodiments claimed herein disclose temporal pulse shaping for laserpulses used in LSP applications. In LSP applications, real timevariation of laser temporal profiles, including variations to both pulsewidth and pulse shape, is beneficial.

For LSP applications, short temporal laser pulses having pulse widths ofless than about 10 ns may produce higher residual stresses on a surfaceof a workpiece, but a depth of residual stress for laser pulses at thispulse width may not adequately penetrate past a surface of a workpiece.Residual stress produced by a longer pulse, for example a pulse width ofabout 20 ns, may penetrate deeper into a workpiece. Thus, better fatigueresistance for a workpiece may be achieved by first processing aworkpiece with a layer of 20 ns laser pulses followed by processing aworkpiece with a layer of 10 ns laser pulses. Workpieces with varyingthicknesses may also present problems in LSP applications requiringlaser pulses with different temporal profiles. It may be beneficial tovary a temporal pulse width of a laser pulse in real time during LSPapplications such that thinner sections of a workpiece may be processedwith shorter laser pulses, and thicker sections be processed with longerlaser pulses in a continuous processing cycle.

With reference to FIG. 1, a schematic view of a system 100 for temporalpulse shaping of a laser pulse 104 is illustrated. System 100 fortemporal pulse shaping of an input laser pulse 104 may include: a laser102, a modulator 106, a waveform generator 108, a high voltage driver112, a polarizer 117, an amplifier 118, and a processing device 132.

Laser 102 may be at least one of: a continuous wave (CW) laser, a CWfiber laser, a diode pumped CW laser, a diode pumped CW fiber laser, anda long pulse laser oscillator. Laser 102 may include a laser crystalsuch as a neodymium-doped YAG (Nd:YAG), neodymium-doped vanadate(ND:YVO₄), neodymium-doped YLF (Nd:YLF), or any other sold-state crystalmaterial, in either a rod or a slab gain medium to produce a pulsedlaser beam. Laser 102 may be configured to produce a pulsed laser beamfor use in LSP applications. Laser 102 may be configured to deliverlaser pulses having: a pulse energy of between about 1 J and about 50 J(at the output of the final amplifier module 118); wavelengths betweenabout 1053 nm and about 1064 nm; and pulse widths of between about 5 nsand about 40 ns. Laser 102 may be configured as single frequency in aTEM₀₀ mode, as TEM₀₀ only, or setup to operate in multimode. As usedherein, “laser” may refer to a laser oscillator alone, or a laseroscillator in addition to optical amplification.

Modulator 106 may be at least one of an electro-optic modulator, anacousto-optic modulator, and an electro-optic Pockels cell. In oneembodiment, modulator 106 is a Pockels cell used with high voltagedriver 112, waveform generator 108, and polarizer 117 to modify atemporal profile of input laser pulse 104. In one embodiment, Pockelscell 106 is a fast modulator operable to modulate in time measurable ina range of nanoseconds to picoseconds. Pockels cell 106 may comprisedifferent types of crystals and cell sizes, and thus require differentlevels of voltage inputs for proper operation. Pockels cell 106 mayrequire a voltage input in excess of 1,000 V and may use high voltagedriver 112 to produce high voltages needed for proper operation. Inanother embodiment, modulator 106 is an acousto-optic modulator usedwith a lower power CW laser beam to cut out a temporal profile of a CWlaser beam. In this embodiment, additional amplifiers are used toamplify a temporal profile cut out of a CW laser beam. Modulator 106 maybe set up in a pulse slicer mode using high voltage driver 112 andpolarizer 117 to produce a temporal profile of desired temporal pulsewidth and temporal pulse shape. In pulse slicer mode, high voltagedriver 112 may provide high voltage signals to modulator 106 to rotate apolarization of input laser pulse 104. If the orientation ofpolarization axis of input laser pulse 104 aligns with an orientation ofa polarization axis of polarizer 117, input laser pulse 104 may passthrough polarizer 117 and further through system 100. In one embodiment,modulator 106 and polarizer 117 are set up to not allow transmission ofinput laser pulse 104. Varying a voltage used to operate modulator 106may vary a degree of transmission, for example between 0-100%, of inputlaser pulse 104 through polarizer 117. Use of modulator 106 in pulseslicer mode may be used to shape a leading and a trailing edge of atemporal pulse profile for input laser pulse 104.

With reference to FIG. 2, a temporal profile 200 of an example inputlaser pulse 104 is illustrated. Temporal profile 200 of input laserpulse 104 may be substantially Gaussian in appearance. Leading edge 222may be sliced off by modulator 106 operating in pulse slicer mode asdescribed above, so as to produce a sharper leading edge 224. Sharpleading edge 224 may provide a faster rise time for input laser pulse104. Trailing edge 226 may also be sliced off by modulator 106 to vary apulse width 228 of laser pulse 104. In one embodiment, rise time oflaser pulse 104 is less than about 5 ns.

Use of modulator 106 in pulse slicer mode may be used to shape a leadingedge 222, and trailing edge 226 of input laser pulse 104, but use ofmodulator 106 in pulse slicer mode alone may not modify an interiorshape 230 of input laser pulse 104 between leading edge 222 and trailingedge 226. Waveform generator 108 used with high voltage driver 112 andmodulator 106 may be used to modify an interior shape 230 of input laserpulse 104. In one embodiment, modulator 106 used with waveform generator108 and high voltage driver 112 are used to vary an amplitude ofinterior shape 230, and thus vary an energy level of input pulsed laserbeam 104. Modulator 106 may be operable to vary a pulse width of inputlaser pulse 104 to a pulse width between about 5 ns and about 40 ns foruse in LSP operations. Modulator 106 may be used to configure inputlaser pulse 104 in various temporal shapes. High voltage driver 112 maybe used to control a modulation, for example, of input laser pulse 104in modulator 106, with a high voltage signal 114 from high voltagedriver 112 to modulator 106. Waveform generator 108 may be operable tocontrol high voltage driver 112, modulator 106, and polarizer 117 byproviding a unique waveform 110 to high voltage driver 112 to control anoutput of high voltage signal 114 from high voltage driver 112 tomodulator 106. Waveform generator 108 may be similar to functiongenerators used to produce different waveforms over a range offrequencies. Waveform generator 108 may produce waveforms 110 such assine waves, square waves, triangle waves, sawtooth waves, and the like.A small voltage, for example from 0 to 5 V may be coupled to waveform110 to vary an amplitude of waveform 110. Thus, by varying waveform andamplitude of waveform 110, a unique signal is provided to high voltagedriver 112 to select a high voltage value to couple to waveform 110 toproduce high voltage signal 114. High voltage signal 114 may be anamplified form of waveform 110. In one embodiment, waveform generator108 produces waves with relatively small periods, for example in theorder of nanoseconds to picoseconds to produce very high frequencywaveforms in a frequency range of 1 GHz to 1 THz. In one embodiment,high voltage driver 112 outputting high voltage signal 114 to modulator106 is controlled by waveform 110 from waveform generator 108.

As used herein, processing device 132 may be a computer, a computerprocessor, and the like, and may comprise memory to store an instructionset, such as software. Processing device 132 may be operable to executean instruction set to control all or some components in system 100.Processing device 132 may be used to transmit one or more triggersignals/instruction sets 134 to waveform generator 108 to generate awaveform 110. Processing device 132 may provide an instruction set 134to waveform generator 108 to create a unique time dependent voltagewaveform 110. A unique waveform 110 may be generated by subdividing awaveform 110 into units of time dependent voltages. In one embodiment,waveform 110 is subdivided into a number of units between 1 unit and1,500 units. Each unit may represent a voltage as a function of time toallow for unique time dependent voltage signals to be created. In oneembodiment, processing device 132 may generate a unique time dependentvoltage signal in lieu of waveform generator 108. Waveform output 110may be used as an input for high voltage driver 112 to create a uniquehigh voltage signal 114. A transmission amount of laser pulse 104 frommodulator 106 through polarizer 117 may be customized depending on highvoltage signal 114 received by modulator 106. Modulator 106 may allowfor 0 to 100% transmission of input laser pulse 104 through modulator106 and polarizer 117, thus shaping a temporal profile of input laserpulse 104. Pulse waveforms 110, that may be operable to produce desiredtemporal pulse shapes of input laser pulse 104 in modulator 106, may bepreloaded into processing device 132, and selected as needed to producedesired temporal pulse shapes for LBI applications. Processing device132 may be integrated into waveform generator 108, or processing device132 may be remote from system 100, and operatively connected to waveformgenerator 108, for example, through trigger signal 134/instruction set134. In one embodiment, a user can program LSP processing instructionsinto processing device 132 for a workpiece of different thicknesses sothat system 100 may provide an “on the fly” modification of a temporalprofile for input laser pulse 104 to impart different magnitudes ofresidual stress, and different depths of residual stress to a workpiece.In this embodiment, LSP is automated and does not require timelyadjustments to the system to account for changes in magnitude and depthof residuals stresses on areas of a workpiece of different thicknesses.

System 100 may further comprise one or more amplifiers 118 that mayamplify a modulated laser pulse 116 output from modulator 106 andtransmitted through polarizer 117. Amplifier 118 may amplify modulatedlaser pulse 116 and output an amplified, modulated laser pulse 120 suchthat amplified, modulated laser pulse 120 may be used for a desired LSPapplication.

A temporal shape of an amplified, modulated laser pulse 120 may bemodified by controlling a shape of modulated input laser pulse 116. Atemporal shape of modulated laser pulse 116 may result in furthertemporal variations in gain derived when modulated input laser pulse 116passes through amplifier 118. A temporal variation of a gainsuperimposed on a temporal shape of modulated input laser pulse 116 maycreate a final temporal shape of amplified, modulated laser pulse 120.Various modifications in a temporal shape of amplified, modulated laserpulse 120 output from system 100 may be used to expand LSP applications.

In one embodiment, a temporal shape modification of amplified, modulatedlaser pulse 120, is a decrease in rise time on a leading edge ofamplified, modulated laser pulse 120. It may be advantageous to minimizea rise time on a leading edge of a laser pulse. A short rise time ofless than about 5 ns on a leading edge of a laser pulse may prevent orpostpone an occurrence of a dielectric breakdown in transparent overlaysused during LSP. By preventing or postponing dielectric breakdowns oftransparent overlays, more laser beam energy from amplified, modulatedlaser pulse 120 may be injected into a target plasma before a dielectricbreakdown of a transparent overlay. A dielectric breakdown of atransparent overlay may block amplified, modulated laser pulse 120.Controlling a temporal shape of laser input pulse 104 may customize aleading edge rise time of amplified, modulated laser pulse 120. In oneembodiment, temporal shaping of input laser pulse 104 to include moreenergy in a leading edge, and less energy in a tail edge of input laserpulse 104, with a gain saturation of modulated laser pulse 116 throughamplifier 118, will decrease a leading edge rise time of amplified,modulated laser pulse 120.

With reference to FIG. 3, an example temporal profile of an amplified,modulated laser pulse 120 is illustrated. Temporal shape modification ofamplified, modulated laser pulse 120, includes a single amplified,modulated laser pulse 120 output with a leading edge part 336 having apulse width of about 20 ns and a trailing edge part 338 having a pulsewidth of about 10 ns with a brief nanosecond delay 340 between eachpulse width. Previously, generation of two individual laser pulses eachwith a different pulse widths would have been required, with each pulserequiring a manual adjustment of an LSP system to set a pulse width foreach pulse. System 100 may be operable to provide a single amplifiedmodulated laser pulse 120 with a temporal pulse shape of varying pulsewidths 336, 338 which may reduce time and costs associated with LSPapplications.

FIG. 4 illustrates a flow chart of an example method 400 which may beused for temporal pulse shaping of a laser beam used in LSP of aworkpiece. In one embodiment, method 400 includes: determining at leastone of a desired magnitude of residual stress, and a desired depth ofresidual stress, at one or more locations on the workpiece, andselecting a pulse width and a temporal profile of a laser beamcorresponding to the at least one of the desired magnitude of residualstress, and the desired depth of residual stress (401); generating alaser beam with a laser and inputting the laser beam into a modulator(403); generating a waveform from a waveform generator, wherein thewaveform is based on selected pulse width and selected temporal profile(405); inputting the generated waveform into a high voltage driver tooutput a high voltage signal (407); inputting the high voltage signalinto the modulator to modulate and shape a temporal profile of the laserbeam with a polarizer based on the selected pulse width and the selectedtemporal profile (409); amplifying the modulated and shaped laser beamwith an optical amplifier (411); delivering the amplified, modulated,and shaped laser beam to the one or more locations on the workpiece(413); and repeating steps 1-7 for each subsequent location on theworkpiece.

The acts of method 400 may also be embedded on a tangible computerreadable medium that may be executed by a computer or like processingdevice to provide one or more instructions to associated hardware forperforming the acts of the method. For example, the act of generating alaser beam with a laser may be executed by a computer and likeprocessing device with instructions sent to corresponding laser hardwareto generate a laser beam.

Unless specifically stated to the contrary, the numerical parameters setforth in the specification, including the attached claims, areapproximations that may vary depending on the desired properties soughtto be obtained according to the exemplary embodiments. At the veryleast, and not as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical parameter shouldat least be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements.

Furthermore, while the systems, methods, and apparatuses have beenillustrated by describing example embodiments, and while the exampleembodiments have been described and illustrated in considerable detail,it is not the intention of the applicants to restrict, or in any waylimit, the scope of the appended claims to such detail. It is, ofcourse, not possible to describe every conceivable combination ofcomponents or methodologies for purposes of describing the systems,methods, and apparatuses. With the benefit of this application,additional advantages and modifications will readily appear to thoseskilled in the art. Therefore, the invention, in its broader aspects, isnot limited to the specific details and illustrative example andexemplary embodiments shown and described. Accordingly, departures maybe made from such details without departing from the spirit or scope ofthe general inventive concept. Thus, this application is intended toembrace alterations, modifications, and variations that fall within thescope of the appended claims. The preceding description is not meant tolimit the scope of the invention. Rather, the scope of the invention isto be determined by the appended claims and their equivalents.

As used in the specification and the claims, the singular forms “a,”“an,” and “the” include the plural. To the extent that the term“includes” or “including” is employed in the detailed description or theclaims, it is intended to be inclusive in a manner co-extensive with theterm “comprising,” as that term is interpreted when employed as atransitional word in a claim. Furthermore, to the extent that the term“or” is employed in the claims (e.g., A or B) it is intended to mean “Aor B or both.” When the applicants intend to indicate “only A or B, butnot both,” then the term “only A or B but not both” will be employed.Similarly, when the applicants intend to indicate “one and only one” ofA, B, or C, the applicants will employ the phrase “one and only one.”Also, to the extent that the terms “in” or “into” are used in thespecification or the claims, it is intended to additionally mean “on” or“onto.” To the extent that the term “selectively” is used in thespecification or the claims, it is intended to refer to a condition of acomponent wherein a user of the apparatus may activate or deactivate thefeature or function of the component as is necessary or desired in useof the apparatus. To the extent that the term “operatively connected” isused in the specification or the claims, it is intended to mean that theidentified components are connected in a way to perform a designatedfunction. Finally, where the term “about” is used in conjunction with anumber, it is intended to include ±10% of the number. In other words,“about 10” may mean from 9 to 11.

What is claimed is:
 1. A system for temporal pulse shaping of a laserbeam used for laser shock processing, the system comprising: a laser; amodulator; a high voltage driver; a waveform generator; a polarizer; andan optical amplifier.
 2. The system of claim 1, wherein the waveformgenerator is operatively connected to the high voltage driver, and anoutput waveform from the waveform generator is input into the highvoltage driver to generate a high voltage output signal.
 3. The systemof claim 1, wherein the modulator is operatively connected to both thelaser and the high voltage driver, and wherein the modulator andpolarizer are operable to receive and modulate the laser beam from thelaser, and wherein the modulator is further operable to receive a highvoltage output signal from the high voltage driver, the high voltageoutput signal operable to control the modulator and modulate the laserbeam as it passes through the polarizer.
 4. The system of claim 1,wherein the laser beam is further rotated in a first polarizationdirection relative to a second polarization direction of the polarizerto vary an energy and amplitude of any of the laser beam passing throughthe polarizer.
 5. The system of claim 1, wherein a high voltage outputsignal input into the modulator shapes a temporal profile of the laserbeam as it passes through the polarizer.
 6. The system of claim 1,wherein the laser comprises at least one of: a continuous wave (CW)laser, a CW fiber laser, a diode pumped (CW) laser; a diode pumped CWfiber laser; and a long pulse laser oscillator.
 7. The system of claim1, wherein the modulator comprises at least one of: an electro-opticmodulator; an acousto-optic modulator; and an electro-optic Pockelscell.
 8. The system of claim 1, wherein the modulator is operativelyconnected to the high voltage driver and the polarizer to modify atleast one of a leading edge and a trailing edge of a temporal profile ofthe laser beam.
 9. The system of claim 1, further comprising aprocessing device, wherein the processing device is operativelyconnected to at least one of the waveform generator and the high voltagedriver, and wherein the processing device is operable to executeinstructions to at least one of: output a time dependent voltage signalfrom the waveform generator, and input a time dependent voltage signalto the high voltage driver, and wherein a time dependent high voltagesignal output from the high voltage driver is operable to shape atemporal profile of the laser beam.
 10. The system of claim 1, wherein apulse width of a temporal profile of the laser beam is between 5 ns and40 ns.
 11. A system for temporal pulse shaping of a laser beam for lasershock processing, the system comprising: a laser operable to produce alaser beam, wherein the laser comprises at least one of: a continuouswave (CW) laser, a CW fiber laser, a diode pumped (CW) laser; a diodepumped CW fiber laser; and a long pulse laser oscillator; a waveformgenerator, wherein the waveform generator is operable to generate a timedependent waveform in response to a trigger signal from a processor,wherein the time dependent waveform is input into a high voltage driver;a high voltage driver operable to output a high voltage signal inresponse to the time dependent waveform input, the high voltage driveroperatively connected to a modulator and a waveform generator; amodulator operable to receive the laser beam, and further operable tomodulate the laser beam with an associated polarizer in response to thehigh voltage signal to output a pulsed and modulated laser beam, whereinthe modulator is at least one of: an electro-optic modulator, anacousto-optic modulator, and an electro-optic Pockels cell; a polarizerassociated with the modulator, comprising a first polarizationdirection; and an optical amplifier, the optical amplifier operable toamplify the pulsed and modulated laser beam to output a pulsed,modulated, amplified laser beam.
 12. The system of claim 11, wherein thelaser beam is further rotated in a second polarization directionrelative to the first polarization direction of the polarizer when thehigh voltage signal is received by the modulator to vary an energy andan amplitude of any of the laser beam passing through the polarizer. 13.The system of claim 11, wherein the modulator is operatively connectedto the high voltage driver and the polarizer, and wherein a pulsedoutput from the high voltage driver is input into the modulator torotate the laser beam in a second polarization direction relative to thefirst polarization direction of the polarizer to modify at least one ofa leading edge and a trailing edge of a temporal profile of the pulsedlaser beam.
 14. The system of claim 11, wherein a pulse width of atemporal profile of the pulsed laser beam is between 5 ns and 40 ns. 15.A method for temporal pulse shaping of a laser beam used laser shockprocessing of a workpiece, the method comprising the acts of: (1)determining at least one of a magnitude and depth of residual stressdesired at one or more locations on the workpiece and selecting a pulsewidth and a temporal profile of the laser beam corresponding to the atleast one of a magnitude of residual stress, and depth of residualstress; (2) generating the laser beam with a laser and inputting thelaser beam into a modulator; (3) generating a waveform from a waveformgenerator, wherein the waveform is based on the selected pulse width andthe selected temporal profile; (4) inputting the generated waveform intoa high voltage driver to output a high voltage signal; (5) inputting thehigh voltage signal into the modulator to modulate and shape a temporalprofile of the laser beam based on the selected pulse width and theselected temporal profile; (6) amplifying the modulated and shaped laserbeam with an optical amplifier; (7) delivering the amplified, modulated,and shaped laser beam to the one or more locations on the workpiece; and(8) repeating acts 1-7 for each subsequent location on the workpiece.16. The method of claim 15, wherein the laser comprises at least one ofa continuous wave (CW) laser, a CW fiber laser, a diode pumped (CW)laser; a diode pumped CW fiber laser; and a long pulse laser oscillator.17. The method of claim 15, wherein the modulator comprises at least oneof an electro-optic modulator; an acousto-optic modulator; and anelectro-optic Pockels cell.
 18. The method of claim 15, wherein thepulse width of the laser beam is between 5 ns and 40 ns.
 19. The methodof claim 15, wherein a processing device is operatively connected to atleast one of the waveform generator and the high voltage driver, andwherein the processing device is operable to execute instructions to atleast one of: output a time dependent voltage signal from the waveformgenerator; and input a time dependent voltage signal to the high voltagedriver, and wherein a time dependent high voltage signal output from thehigh voltage driver is operable to shape a temporal profile of the laserbeam.